cob vs quantum
- Thread starter music64
- Start date
NGA
Well-Known Member
Don't think your height thing is right ,I have 14 boards over 5x9 and some are within 6 inch away from the girls no sign of burn ,I've been a hps guy 30 plus years I have no problem running 3 1k bulbs in that room maybe soil you would have a problem not with hydro ,I will also mention I have no regrets buying these board burning less than 1/2 the usual power
InTheValley
Well-Known Member
Yeah, thats the one i got, but never got in the mail.
as far as Nukeheads, ( Cody ) PAR meter, I know he put alot of time into it, and calibrating the SOFTWARE integrated into the meter. Never needs calibrated i guess, and is more accurate and stable readings then anything under $500, but is supposedly better the Apogee600, so thats says alot. But also, since alot of LEDs do you the realy Far reds, this meter integrates the waves into the calculations or something like that, lol..His video explains it alot.
InTheValley
Well-Known Member
Yeah, i think because that was the LED industry hobby standard meter available without breaking the bank. Plus, thats what he was using before he made his own. But Ive seen several videos, read several reviews, and the Hydrofarm is pretty much a Lux meter with filters, where as Cody's PAR meter, uses real data to get the figures. From what Ive seen, Id have to say he has the best meter, especially for the Price,
wietefras
Well-Known Member
It's what the manufacturer advises and also what was shown in PPFD matrix to be optimal. You might not burn the plants, but you get very uneven uniformity.
Perhaps you are talking at minimum distance to a very tall bud here and there. That's not "the height". A board or COB at 6" does not cover a 3 sqft area uniformly. In that case it would be more like 14".
The point is that you can get the same efficiency for less money with strips or COBs.
wietefras
Well-Known Member
It's been shown to measure quite close to the PAR reference, but apparently it breaks down a lot. Look at the reviews where people say it breaks down after a few weeks or months. Seem like you can mod it to be less likely to break or to repair it after it broke.
wietefras
Well-Known Member
So what? That's what they all do. The filters correct the sensor sensitivity to measure 400-700nm.
What is worse is when the meter needs software to calculate values to correct for an incomplete filter. Which is what the older Apogee sensors did. You could sort of adjust the correction factor, but that just never works accurately.
What does that even mean? "real data"?
far red is around 730nm which doesn't fall within the par range, so how would adding that to the measurement improve accuracy?
Are you talking about the (older) apogee meters which don't read the whole bit above 650nm?
Sounds a lot like vague / false advertising comparing the readings to an already poor and obsolete sensor.
Humple
Well-Known Member
I think the COB vs QB argument changes a little when you look at the QB120 and QB132. Using CobKits' pre-built light engines as an example of a COB setup that's as easy to put together as QBs are, the cost to outfit a fixture with one COB per square foot would be a little more than that of the QBs. Now I'm sure you can put together a COB build for less than that if you're buying components separately, but for the grower who wants an easier build, why not opt for the diode-spread of the boards? It would certainly bring you closer to the kind if uniformity achieved by strips, no? I can tell you from personal experience that you can slam QB120s right on top of the plants without adverse effect.
I do understand the argument that one COB per square foot can achieve greater uniformity than QB288s, but no one ever considers the lower diode-count boards in this debate. When positioned properly, they really are very similar to strips (and a hell of a lot easier for your average Joe to build).
All that said, strips still seem to be the winner, by every metric I can think of (except for the ease of building part of the equation).
I do understand the argument that one COB per square foot can achieve greater uniformity than QB288s, but no one ever considers the lower diode-count boards in this debate. When positioned properly, they really are very similar to strips (and a hell of a lot easier for your average Joe to build).
All that said, strips still seem to be the winner, by every metric I can think of (except for the ease of building part of the equation).
InTheValley
Well-Known Member
Yeah, i probably Fkd the explanation all up, lol,
InTheValley
Well-Known Member
we wont have a true grip till we get a bunch of folk growing the same beans, the same medium, the same environment, different light rig.
But i rarely see Colas as big as HPS with QBs. where as with COBS, ive seen some meaty colas. Like Greengenes PLC, that sucker is badass, and Id take that over the QBs or strips.
BigGreenThumb had some nice colas, but he had sidelighting and what, like 4000Watts, I cant remembers.
So, lets see some QB pics of beer can colas, post em if you got them.
Utube has the same 3 QB sells man advertisers, but not huge colas.
But i rarely see Colas as big as HPS with QBs. where as with COBS, ive seen some meaty colas. Like Greengenes PLC, that sucker is badass, and Id take that over the QBs or strips.
BigGreenThumb had some nice colas, but he had sidelighting and what, like 4000Watts, I cant remembers.
So, lets see some QB pics of beer can colas, post em if you got them.
Utube has the same 3 QB sells man advertisers, but not huge colas.
wietefras
Well-Known Member
Because their shape is still not the most sensible to use in a grow room. A led strip or a row of COBs covering the whole depth of the grow just makes more sense.
How is it difficult to build a regular strip frame? Those are by far the easiest lights I have made.
If you want to lower cost of a COB build then attach the COBs to aluminium strips. That way you won't need a cooler per COB. I made 90W "6 COB led strips" that way. In my case from 3 year old COBs, but it would work equally well (probably better) with smaller COBs like the Citizen 1212.
Humple
Well-Known Member
I'd love to see a real world side-by-side.
wietefras
Well-Known Member
COBs, led strips and boards all produce exactly the same light. When using the same light intensity, I'm not sure what would be the reasoning to expect a different outcome from any of these.
At best you could see some difference between light sources. ie 1 COB or board per 2'x2' vs 1 light source per sqft. Although I've seen side-by-sides where even that didn't make any difference with similar intensities (apart from g/W being higher with more light sources)
At best you could see some difference between light sources. ie 1 COB or board per 2'x2' vs 1 light source per sqft. Although I've seen side-by-sides where even that didn't make any difference with similar intensities (apart from g/W being higher with more light sources)
InTheValley
Well-Known Member
Its just 1 part of the program. Best lights wont grow shit if you dont do everything else at least halfassed. There are soooooo many variables to growin this plant, and thats what makes it so enjoyable, and so mind refreshing, and at the same time, so mind boggling when you first get going. AND, the banter from everyone is also awesome. Battle of the minds and guruizm. lol..
Humple
Well-Known Member
I'm genuinely not trying to start an argument (I'd lose anyway!), but I'm not grasping why - if COBs are superior - there shouldn't be an appreciable difference at the same intensity? My understanding of your assertion is that one COB per square foot will afford better uniformity than one board per square foot, yes? If so, that improvement in uniformity should be measurable, correct?
wietefras
Well-Known Member
Because the whole uniformity issue is mostly rooted in what height you need above the canopy and therefore how much light is wasted on the walls. You hang the lights for correct uniformity. Which means that in the end it's only a matter of efficiency of getting light on the plants (mostly in wall losses). Once you get the same amount of light on the plants there is not much difference anymore. Mostly just that you will be using more or less electricity.
It's more like one COB per sqft vs a single board per 4 sqft. Those QB288 boards are designed for a 2x2 area. You'd normally put about 4 COBs over the same area or two led strips.
Humple
Well-Known Member
Yeah, I get the comparison between a single QB288 and four COBs, and your concerns about hanging height and wall losses - no argument there. I'm just hypothesizing that four QB120s or QB132s - in the same space, and at the same power - could at least match the uniformity of four COBs, without greater wall losses. Not saying that it's true, just that I'd like to see the comparison done. Because if it worked out that way, the QB build would definitely be easier for many people who are new to this, due to the lack of heatsinks. I'm not anywhere near your level of education on this subject, so I'm not presuming to any firm claims, but it's difficult for me to understand how four COBs in a 2x2 could be hung any closer than four boards with the kind of spread the no-heatsink QBs have. My top colas are practically kissing the diodes on my 120s (each of which runs a little over 60 watts). Not having run COBs, I don't have an experiential point of reference, but sticking with the example of a 2x2 space, let's assume 40 watts per COB: how close would you let the plants get to a COB running that power? I'm guessing that you wouldn't want to let them get too close, because then the rest of the plant wouldn't be getting as much light as it would if you kept the fixture further away, yes? But with the boards, the diodes are so spread out that even at such a close distance, the rest of the plant is getting blasted by other rows of diodes. So I guess what I'm thinking of is a veritable ceiling of light. To my layman's mind, that seems like it would accomplish greater uniformity than four distinct points of light coming from four COBs.
wietefras
Well-Known Member
Well 4 boards would probably be slightly be better than 4 COBs yes. I'd say four 2' single row led strips would still perform better though.
BTW it's surprising how quickly the light blends. At 18" you won't see a significant difference between a COB and a Board in uniformity. After about a centimeter a led strip blends into a blurred strip of light. You won't see distinct leds anymore with a light meter.
CobKits
Well-Known Member
a lot of that depends on how hard you run the board. somebody could be running 150w and you are running 50W...with different height requirements
umols on the wall wont make your tent grow
